Tropical cyclone Katarina. Source: Pixabay

EXPERT REACTION: World scientists declare climate emergency

Embargoed until: Publicly released:

A global coalition of more than 11,000 scientists from more than 150 countries has endorsed a declaration of a climate emergency and supported six clear measures by which to reduce the impact of climate change. The paper in BioScience is co-written by University of Sydney biologist Dr Thomas Newsome.

Journal/conference: BioScience

Link to research (DOI): 10.1093/biosci/biz088

Organisation/s: The University of Sydney, The University of Melbourne, The University of New South Wales, Southern Cross University

Funder: The Worthy Garden Club provided partial funding for this project.

Media Release

From: The University of Sydney

·      Declaration endorsed by more than 11,000 scientists
·      Six steps to address the impact of global warming established

A global team of scientists including Dr Thomas Newsome at the University of Sydney and international colleagues has warned that “untold human suffering” is unavoidable without deep and lasting shifts in human activities that contribute to greenhouse gas emissions and other factors related to climate change.

The declaration is based on scientific analysis of more than 40 years of publicly available data covering a broad range of measures, including energy use, surface temperature, population growth, land clearing, deforestation, polar ice mass, fertility rates, gross domestic product and carbon emissions.

“Scientists have a moral obligation to warn humanity of any great threat,” said Dr Newsome from the School of Life and Environment Sciences. “From the data we have, it is clear we are facing a climate emergency.”

In a paper published today in BioScience, the authors from the University of Sydney, Oregon State University, University of Cape Town and Tufts University, along with more than 11,000 scientist signatories from 153 countries, declare a climate emergency, present data showing trends as benchmarks against which to measure progress and outline six areas of action to mitigate the worst effects of a human-induced climate change.

“Despite 40 years of major global negotiations, we have generally conducted business as usual and are essentially failing to address this crisis,” said Professor William Ripple, distinguished professor of ecology in the Oregon State University College of Forestry and co-lead author of the paper. “Climate change has arrived and is accelerating faster than many scientists expected.”

Dr Newsome said that measuring global surface temperatures will continue to remain important. However, he said that a “broader set of indicators should be monitored, including human population growth, meat consumption, tree-cover loss, energy consumption, fossil-fuel subsidies and annual economic losses to extreme weather events”.

He said the indicators are intended to be useful for the public, policymakers and the business community to track progress over time.

“While things are bad, all is not hopeless. We can take steps to address the climate emergency,” Dr Newsome said.

The scientists point to six areas in which humanity should take immediate steps to slow down the effects of a warming planet:

1)    Energy. Implement massive conservation practices; replace fossil fuels with clean renewables; leave remaining stocks of fossil fuels in the ground; eliminate subsidies to fossil fuel companies; and impose carbon fees that are high enough to restrain the use of fossil fuels.

2)    Short-lived pollutants. Swiftly cut emissions of methane, hydrofluorocarbons, soot and other short-lived climate pollutants. This has the potential to reduce the short-term warming trend by more than 50 percent over the next few decades.

3)    Nature. Restrain massive land clearing. Restore and protect ecosystems such as forests, grasslands and mangroves, which would greatly contribute to the sequestration of atmospheric carbon dioxide, a key greenhouse gas.

4)    Food. Eat mostly plants and consume fewer animal products. This dietary shift would significantly reduce emissions of methane and other greenhouse gases and free up agricultural lands for growing human food rather than livestock feed. Reducing food waste is also critical – the scientists say at least one-third of all food produced ends up as garbage.

5)    Economy. Convert the economy’s reliance on carbon fuels to address human dependence on the biosphere. Shift goals away from the growth of gross domestic product and the pursuit of affluence. Curtail the extraction of materials and exploitation of ecosystems to maintain long-term biosphere sustainability.

6)    Population. Stabilise global population, which is increasing by more than 200,000 people a day, using approaches that ensure social and economic justice.

The paper states: “Mitigating and adapting to climate change means transforming the ways we govern, manage, eat, and fulfil material and energy requirements.

“We are encouraged by a recent global surge of concern – governments adopting new policies; schoolchildren striking; lawsuits proceeding; and grassroots citizen movements demanding change.

“As scientists, we urge widespread use of the vital signs and hope the graphical indicators will better allow policymakers and the public to understand the magnitude of the crisis, realign priorities and track progress.”

The graphs illustrate how climate-change indicators and factors have changed over the past 40 years, since scientists from 50 nations met at the First World Climate Conference in Geneva in 1979.

In the ensuing decades, multiple other global assemblies have agreed that urgent action is necessary, but greenhouse gas emissions are still rapidly rising. Other ominous signs from human activities include sustained increases in per-capita meat production, global tree cover loss and number of airline passengers.

There are also some encouraging signs – including decreases in global birth rates and decelerated forest loss in the Brazilian Amazon and increases in wind and solar power – but even those are tinged with worry.

The decline in birth rates has slowed over the last 20 years, for example, and the pace of Amazon forest loss may be starting to increase again.

“Global surface temperature, ocean heat content, extreme weather and its costs, sea level, ocean acidity and land area are all rising,” Professor Ripple said.

“Ice is rapidly disappearing as shown by declining trends in minimum summer Arctic sea ice, Greenland and Antarctic ice sheets, and glacier thickness. All of these rapid changes highlight the urgent need for action.”

Joining Dr Newsome and Professor Ripple are co-lead author Dr Christopher Wolf, a postdoctoral scholar in the Oregon State University College of Forestry; Dr Phoebe Barnard of the Biological Conservation Institute and the University of Cape Town; and Emeritus Professor William Moomaw of Tufts University.


VIDEO explainer of the climate emergency declaration.
Available in 16:9 and square ratios, with or without subtitles.
Download at this link.

PHOTOGRAPHS of Dr Thomas Newsome and PDF of research at this link.

The Worthy Garden Club provided partial funding for this project.


  • The University of Sydney
    Web page
    Videos in 16:9 ratio, with and without subtitles; square ratio, with and without subtitles

Expert Reaction

These comments have been collated by the Science Media Centre to provide a variety of expert perspectives on this issue. Feel free to use these quotes in your stories. Views expressed are the personal opinions of the experts named. They do not represent the views of the SMC or any other organisation unless specifically stated.

Professor Caroline A Sullivan is Establishment Director of the National Centre for Flood Research and Professor of Environmental Economics and Policy in the School of Environment, Science and Engineering at Southern Cross University

Bioscience has provided the opportunity for the climate crisis to be discussed once again, and the fact that over 11,000 scientists have been a signatory to this warning must surely be seen by all as an indication of the seriousness of this problem. This is not just some kind of anti-oil propaganda, or a message from greenie tree huggers - these are thousands of scientists from across the world from the whole range of disciplines relevant to this issue.

The comprehensive analysis provided in this paper leaves no room for doubt, as the evidence is all there.  In the face of this, what we need to ask ourselves is, what kind of future do we want?, and how do we get there?   Does the human race really want to get into the state where we have fouled our own nest and can only survive if we flee to hostile and distant alternative planets?  Would it not be better for our future to be one of prosperity and equity, so we can go forward into our galaxy as a strong and powerful species which is a force for good?  If that is our choice, then surely we must take heed of this warning, to act on how we generate and use energy, how we feed ourselves, and how we manage our social and economic trajectory into the future.

Last updated: 05 Nov 2019 5:39pm
Declared conflicts of interest:
None declared.
Dr Linden Ashcroft is a Lecturer in climate science and science communication at The University of Melbourne

This article adds to the roar from all fields of science that climate action needs to be taken now.
The succinct summary shows clearly how much has changed in our environment, population, and energy sectors in the last 40 years. While there are some good signs, the majority of the graphs in this article are going up, when they need to be going down.
The impressive signatory list contains at least 350 Australian scientists, with more ecologists and medical researchers than climate researchers. This suggests to me these experts are reacting to the devastating impacts they see in their everyday work.
Breaking down our choices into six areas will be confronting for some, but the reality is that we need to make big changes—and quickly—to avoid the worst impacts of climate change.
Australia is not immune to this: in the last 40 years we have already seen an increase in heatwaves, a decrease in rainfall across parts of our south, and a lengthening of the bushfire season.

Last updated: 05 Nov 2019 12:41pm
Declared conflicts of interest:
None declared.
John Church is a Professor in the Climate Change Research Centre, University of New South Wales.

The data presented here is a cause for great alarm at the pace at which we are trashing our planet.  But they also reveal signs of hope for the future. We know what to do, and we have demonstrated we have the tools.  If we can only muster the will we can still prevent dangerous climate change.

Last updated: 05 Nov 2019 12:40pm
Declared conflicts of interest:
None declared.

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